Expand Index struct to also get the original field name

This is needed in postgres, since we store data as jsonb so struct
fields can't get renamed

Signed-off-by: Lee Smet <lee.smet@hotmail.com>

heromodels-derive/src/lib.rs

@@ -169,6 +169,10 @@ pub fn model(_attr: TokenStream, item: TokenStream) -> TokenStream {
                 fn key() -> &'static str {
                     #index_key
                 }
+
+                fn field_name() -> &'static str {
+                    #name_str
+                }
             }
         };
 

heromodels/src/models/biz/company.rs

@@ -84,6 +84,9 @@ impl Index for CompanyNameIndex {
     fn key() -> &'static str {
         "name"
     }
+    fn field_name() -> &'static str {
+        "name"
+    }
 }
 
 pub struct CompanyRegistrationNumberIndex;
@@ -93,6 +96,9 @@ impl Index for CompanyRegistrationNumberIndex {
     fn key() -> &'static str {
         "registration_number"
     }
+    fn field_name() -> &'static str {
+        "registration_number"
+    }
 }
 
 // --- Builder Pattern ---

heromodels_core/src/lib.rs

@@ -83,6 +83,11 @@ pub trait Index {
 
     /// The key of this index
     fn key() -> &'static str;
+
+    /// The original field name. This is the same as [Index::key] by default, unless the user
+    /// specified a `(name=...)` value to the index attribute, in which case [Index::key] will be
+    /// set to the specified key.
+    fn field_name() -> &'static str;
 }
 
 /// Base struct that all models should include